Find at What Time Do the Wheels Leave the Ground

Solve the all parts of given question:

Question: The takeoff speed for an Airbus A320 jetliner is 74m/s. Velocity data measured during takeoff are as follows: t(s) 0 10 20 30 40 Vx (m/s) 0 20 40 60

Part A: At what time do the wheels leave the ground?

Part B: For safety reasons, in case of an aborted takeoff, the length of the runway must be three times the takeoff distance, what is the minimum length runway this aircraft can use? I need help to solve the above question and express your answer to two significant figures and include the appropriate units.